Air cellular cushioning articles suitable for packaging applications have been in commercial use for several decades. One of the products in widespread commercial use is BubbleWrap® cellular cushioning, one embodiment of which is made using heat and vacuum to form spaced-apart air-filled cavities in a first film and thereafter heat sealing a flat “backing” second film to the flats between the cavities of the first film, so that air is entrapped in each of the formed cavities making up the individualized cells. The resulting air-cellular cushioning product comprises discrete closed bubbles. If any one bubble deflates, no other bubble necessarily deflates. One significant disadvantage of BubbleWrap® cellular cushioning is that shipping costs are high per unit weight of product because the product density is low, i.e., the shipping of such products is mostly shipping air.
Although Bubble Wrap® cellular cushioning products have not been significantly displaced by inflatable flexible cushioning articles, in the past there have been a number of commercialized air-cellular cushioning products for packaging which have been designed to be inflated by the end user, i.e., inflated and sealed shut immediately before end use by the packager. These products offer the advantage of being shippable before inflation, providing for much more efficient transport and storage before use, as any given volume within a truck or warehouse can hold over thirty times as much product (on a weight basis) if it is uninflated rather than shipped to the packager while inflated.
Flat films which are sealed together to make an inflatable cellular cushioning product exhibit a disadvantage of widthwise contraction upon inflation. One way to reduce widthwise contraction upon inflation is to thermoform one of the films as disclosed in U.S. Pat. No. 6,423,166, to Simhaee. However, this product exhibits the disadvantage of having to remove entrapped air from the volume between the bubble sheet and the base layer, in order to achieve a higher density product which provides the advantage of more efficient transport and storage.
It would be advantageous to provide a cellular cushioning article having the density advantage of an uninflated, inflatable product without having to remove air from within the cells. The removal of air is a process step which is time-consuming and difficult to carry out, especially to the degree of substantially complete removal, or complete removal, of the air from between the two films.